Insulator



Aug. s, 1933. L FRT 1,920,978-

INSULATOR Filed Augl 29, 1929 A INVENTOR Z au15 For? ATTORN EY Patented Aug. 8, 1931"V UNITED INS'IOR Louis Fort, .llersey mty, N. ll.

Application August 29, 11929.

Seriali No. 389,I7ll

'l Claims.. (Cl. *IW-314i) In the installation of electrical power lines, it is very essential, in order to preventleakage to ground, to properly insulate the lines from their supports. For this purpose, various types of insulators have been devised, one of which `is known to the trade as the pin type insulator, and it is to such insulators larly relates.

The poles on which power lines are strung are generally equipped with cross-arms to which pins for the insulators are secured by means of bolts. Frequently the pin and the bolt are made integral, the pin being provided with a threaded portion onto which the insulator is screwed. The insulator, which is commonly glass or porcelain, is hollow and internally screw threaded for its attachment to the pin. The upper portion of the insulator is provided with a circumferential groove in which the wire is laid, or with a bore through which the wire is threaded. The wire is secured to the insulator by means of a short added piece of wire, commonly called a tie wire. In such installation, it is not uncommon for the wire to become loosened from the insulator or the insulator to become broken or loosened on the pin. In the event of any of the above happening, the wire is very likely to sag and become grounded or broken, thereby tying up the entire line until the trouble may be located and corrected.

By my invention, the chance of line failure resulting from insulator troubles is verymaterially reduced. I provide an insulator which has a projectionthat carries a pin rigidly secured thereto for attaching the insulator to the crossarm or other support.

Among the characteristics of my invention is the fact that the line wire is securely clamped to the insulator by a cooperating insulator strap which is bolted to the insulator by through bolts.

An important feature of my invention is the fact that the attaching stem may be provided with a combined metal reinforcing cap and screw or machine bolt for fastening lthe insulator tol the support, the shank of the bolt being rigidly secured to the cap. I `The reinforcing cap coupled to the bolt shank relieves the porcelain stem or foot of the insulator of strains when making up.

Another important feature of my invention is the fact that the clamping piece may be reinforced with a bridge of flat iron or a U-shape bolt reinforcing the cap so that in case of breakage of the clamping strap, the wires can not be unfastened from the insulator. This metal rethat my invention particuinforcement does not interfere'with the insulating qualities of the insulator to ground.

Specifically, I provide an insulator having a disk or mushroom head which has a groove in one surface thereof adapted to receive a wire, and a stem extending from the opposite face. On the surface in which the groove is formed, the disk head of-the insulator is provided with four lugs or projections which in one direction constitute positioning members for a clamping strap which is received between them, and in the direction at right angles thereto constitute open continuations of the wire receiving groove. In the latter direction the faces of the lugs are rounded to present easy bending surfaces to the wire. The clamping strap which is formed from the same material as the rest of the insulator is adapted to be secured to the insulator by through bolts extending through the disk head, The end of the stem carriesl a lag screw, machine bolt or foot, the shank of which is embedded in the end of the stem and is rigidly secured thereto. Reinforcement may be provided for the clamping strap in the form of a bridge of flat iron or a U-shape bolt, and for the stem in the form of a reinforcing cap rigidly secured to the stem of the bolt.

Other features and advantages of my invention will hereinafter more particularly appear.

I shall now describe the illustrated embodiment of my invention in connection with the accompanying drawing in which:

Fig. 1 is an elevation of a pin insulator embodying my invention, the lower part of the projector being shown in section;

Fig. 2 isa'plan of the same with the clamping strap removed;

Fig. 3 is an elevation of the clamping strap with the reinforcing U-shape bolt in place; and

Fig. 4 is a plan of the lower face of the clamping strap.

In the illustrated embodiment of my invention, there is shown a pin insulator which comprises a mushroom or disc head 1, a clamping .strap 2 which is lto be secured to the head 1 by means of a U-shape bolt 3, and a stem 4 to which the shank of a machine bolt 5 is rigidly secured. y

The muchroom or disc head l which has a groove adapted to receive the wire is provided with four lugs or projections 6 to form a suitable guide and support for the wire and a sup-A port `for the clamping strap. The faces of the projections which form a guide for the wire` are designed to allow an easy sweepl or curve 110 of the wire in cast it changes direction after attachment to the insulator, and eliminate any abrupt angles in the wire which would be detrimental to the insulation on the wire, and'avoid crystallization of the wire at the bending point. The clamping faces la of the groove in which the wire is laid, are desirably serrated as shown to afford a more effective gripping of.v thewire and allow for the escape of moisture. A longitudinal recess in the section of the`groove in both the strap and the head communicates with the serrations and a free circulation of air about the portion of the wire within the groove is thereby provided. On either side of the clamping face of the insulator head i, the insulator is bored to receive through bolts for the purpose of se-V curing the clamping strap 2.

The clamping strap 2 is constructed in the shape shown and has a central transverse groove which is adapted to cooperate with the groove in theV insulatorhead. The clamping faces 2a of the groove in the clamping strap are serrated in a manner similar tothe clamping faces of the g'oove in the insulator. Holes are bored in the clamping strap in alignment with the holesy in the insulator head. The legs of the iJ-shape bolt 3 are adapted to pass down through ythe aligned holes'in tle clamping strap and insulator' and firmly clamp the strap 2 to the insulator. Itis to be noted that in case of breakage of the clamping strap, the U-shape bolt will prevent the wire from becoming disconnected from the insulator.

The stem 4 extending from the lower surface of the insulator head is formed integral therewith and is provided with a depression in the lower end which is adapted to receive the shank 5a of the machine bolt 5. The shank of the machine bolt may be rmly fastened into the insulator stem by filling the opening around the shank with babbit metal or the like. In the illustration shown, a reinforcing cap 'I is combined with the shank of the machine bolt 5 and fits over the end of the stem 4, the extension of the shank fitting into the depression in the end of the stem. In this construction, as in that where the bolt is used without a reinforcing cap, the bolt and the cap are firmly secured to the stem by babbit metal or the like. The cap '7 will preferably be non-circular to avoid loosening of he cap on the stem 4 if a turning force is ap lied vto the headxof the insulator .to lscrew the stem.

5 into the support.

An insulator constructed as above describedV is rigid, durable and complete "in itself. Such an insulator possesses the advantage of rmly clamping the wire between two complementary grooves having serrated faces, the clamping strap 'being secured in place by through bolts which extend through the strap and insulator.

Insulators of this type may also be used'for insulating bus-barsand uncovered wires from their supports. v

It is obvious that various modifications may bevmade in the illustrated embodiment above particularly described within the principle and scope of my invention as expressed in theappended claims. Y.

I claim:

1. An insulator for use in insulating electric conductorsffrom their supports comprising a disk formed from insulating material constituting` the head and havinga diametrical groove in one surface thereof adapted to accommodate a conducgroove in the head, clamping means for securing said clamping strap to said head, and means carried by the insulator for attaching the insulator to the support. f

2. An insulator for use in insulating conductorsv from 4their supports comprising a disk formed from insulating material constituting the head and having a diametrical groove in one surface thereof adapted to accommodate a conductor,

projections extending from the surface of said head containing the groove and having curved surfaces forming a continuation of the sides of the groove in said head, ar removable clamping strap formed from insulating material and having a complementary transverse groove in' the lower surface thereof and fitting between said projections transversely of the groove in the head, clamping means constituting areinforcement for said clamping strap for securing the strap to the head, and means carriedby the insulator for attaching the insulator to the support.

3. An insulator for use in insulating conductors from their supports comprising a disk formed from insulating material constituting the head and having a diametrical groove in one surface thereof adapted to accommodate a conductor, projections extending yfrom the surface ofthe head containing the groove and having curved 110 surfaces forming a continuation of the groove in the head, a removable clamping strap formed from insulating material having a complementary .a reinforcement for said clamping strapfor securing the strapto the head and clamping a' conductor between the strap and the head, a stem formed from insulating material extending from the surface of said head-opposite to the surface containing the groove, said stem being of lesser diameter than the head, and means carried by l the stem for attaching the insulator to a support.

4. An insulator for use in insulating conductors. from their supports comprising a disk formed from insulating material constituting the head and having a groove in one surface thereof adaptedto receive a conductor, projections extending from said head,` a removable clamping strap formed from insulating material having a complementary transverse groove in one surface thereof `:and fittingv between said projections transversely of the groove in the head, and a U-shaped bolt ifor securing the clamping strap to the head, the head and the clamping strap having aligned openings to receive the legs of the bolt.

5. An insulator for use in insulating conductors from and securing conductors to their supports comprising a disk formed from insulating lmaterial constituting the head and having a di- Leaders strap having a transverse groove formed therein cooperating with the conductor groove in the head, clamping means for securing the clamping strap to the insulator head and clamping a conductor between the strap and the head, a stem formed from insulating material extending from the surface of said head opposite to the surface containing the conductor groove, saidstem being of lesser diameter than the head, and means carried by the stem for securing the insulator to a support.

6. An insulator for use in insulating conductors from and securing conductors to their supports comprising a disk formed from insulating material constituting the head and having a diametrical groove in one surface thereof foraccommodating a conductor, four projections extending from the surface of the head containing the groove and forming two grooves one parallel to the conductor groove in the head and the other at right angles thereto, a removable clamping strap extending diametrically across the head at right angles to the conductor groove and fitting between the aforementioned projections, said strap having a transverse groove formed therein cooperating with the conductor groove in the head, clamping means for securing the clamping strap to the insulator head and clamping a conductor between the strap and the head, a stem formed from insulating material extending from the surface of 'said head opposite to the surface containing the conductor groove, said stem being of lesser diameter than said head and -the surface of the head containing the conductor groove and forming two grooves, one a continuation of the conductor groove and the other at right angles thereto, a removable clamping strap extending diametrically across the head at right angles to the conductor groove and tting between the aforementioned projections,

said strap having a transverse groove formed therein opposite the conductor groove in the head, said clamping strap and said head having aligned openings therethrough at diametrically opposite points, a U-shape bolt forsecuring the clamping strap to the head and reinforcing the clamping strap, the boit extending longitudinally of the strap and the arms thereof extending through the aligned opening inthe strap and the head, a stem extending from the surface of theA head opposite to the surface containing the conductor groove, said stem being of lesser diameterl than said head and tapering outwardly towardsl its free end, and means rigidly secured in the free end for securingthe insulator to the support.

LOUIS FORT. 

